1. Field of the Invention
The present invention relates in general to an evaporative emission control system of a motor vehicle, and more particularly to a fuel tank vent system which comprises a fuel tank and a vapor separator.
2. Description of the Prior Art
The fuel tank is vented to allow vapors and air to move in and out of the tank in order to keep the inside pressure nearly equal to the outside pressure as the vehicle goes up and down hills, as atmospheric pressures change, and as fuel is drawn from the tank. On emission control motor vehicles, the fuel tank is vented through a vapor separator and a carbon canister. The carbon canister traps the vapors to keep them from entering the atmosphere. On restarting of the engine, a flow of filtered air through the canister purges the vapors from the canister. The mixture goes through one or more tubes feeding into the carburetor and/or carburetor air cleaner and it is burned in the engine.
Usually, the vapor separator is a separate device which is mounted within the fuel tank, more specifically, at an upper vacant portion of the interior of the same. However, when the fuel tank is of one piece construction of moulded plastics, the work for mounting a vapor separator in the fuel tank requires the employment of skilled labor and time because of the indivisible construction of the tank. Although formation of a large opening in the upper wall of the tank may facilitate the work for inserting and assembling the separator in the tank, this method reduces the mechanical strength of the tank to a considerable degree.